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Computer Skills Preparatory Year 2011-2012 Presented by: L.Obead Alhadreti.

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Presentation on theme: "Computer Skills Preparatory Year 2011-2012 Presented by: L.Obead Alhadreti."— Presentation transcript:

1 Computer Skills Preparatory Year Presented by: L.Obead Alhadreti

2 Last week - Lecture 1 The definition of the computer The history of computers The types of computers

3 Lecture 2 - Outline The main parts of the Personal Computer Computer Hardware Memory Measurement Factors that Impact on a Computer's Performance

4 Main parts of the PC Computers Have Two Main Parts: Hardware: The term hardware refers to the physical components of your computer which you can physically touch or see such as your monitor, case, disk drives, microprocessor and other physical parts. Software The software is the instructions that makes the computer work. Software is held either on your computers hard disk, CD-ROM, DVD or on a floppy disk and is loaded from the disk into the computers RAM, as and when required.

5 Main parts of the PC

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8 Hardware: Hardware can be categorised into: Input Units, Output Units Central processing Unit, Memory Unit (main memory), and Storage devices (secondary memory).

9 Main parts of the PC Input Units: Input units: those parts of the compute receiving data to programs. 1. The Mouse A small hand-held device which has the shape of mouse. enhances users ability to input commands, manipulate text, images.

10 Main parts of the PC 2. The Keyboard The keyboard is still the commonest way of entering information into a computer. 3. Tracker Balls an alternative to the traditional mouse and often used by graphic designers 4. Scanners A scanner allows you to scan printed material and convert it into a file format that may be used within the PC.

11 Main parts of the PC 5. Touch Pads A device that lays on the desktop and responds to pressure. 6. Light Pens Used to allow users to point to areas on a screen. 7. Joysticks Many games require a joystick for the proper playing of the game.

12 Main parts of the PC Output Units: Output Units: those parts of the computer that provide results of computation to the person using the computer. 1. Monitors: are the most commonly used output device. used for outputting information in an understandable format for humans.

13 Main parts of the PC 2. Printers There are many different types of printers: dot matrix, ink jet, and Laser. In large organizations laser printers are most commonly used due to the fact that they can print very fast and give a very high quality output 3. Plotters A plotter is an output device similar to a printer, but normally allows you to print larger images.

14 Main parts of the PC 4. Speakers Enhances the value of educational and presentation products.

15 Main parts of the PC Central Processing Unit: the Central Processing Unit (CPU), also called a processor, or a microprocessor, is the brains within your computer. It performs the arithmetic and logical process within the computer. made up from a semiconductor, Silicon. contain hundreds of millions of transistors which are interconnected through extremely fine wires made of copper. it determines how fast your computer will run. The speed (clock speed) of CPU measured by Hertz (MHz) and (GHz). measured by its Hertz speed (e.g. MHz, GHz). A processor with speed of 600 MHz is much faster than a processor with speed of 400 MHz. processor manufacturers: Intel, AMD, and Cyrix processor. CPU types: Intel Pentium, Intel Celeron, and AMD Athlon.

16 Main parts of the PC The CPU consists of : Control Unit (CU): coordinates all activities of the computer by determining which operations to perform and in what order to carry them out. Arithmetic and Logical Unit (ALU): perform arithmetic operations (addition, subtraction, multiplication and division), and Logical operations (and, or, not, …) and to make some comparisons (less-than, equal, … etc.) Some Registers: where the data used by ALU are stored. enjoy watching:

17 Main parts of the PC Memory Unit: 1. RAM: The RAM (Random Access Memory) is where the operating system is loaded and also where your applications, such as word processor, are copied. It saves the computer data temporarily while the program is running. It loses its contents if power is disconnected (volatile memory). 2. ROM: The ROM (Read Only Memory)is a special chip held on your computer's system (mother) board. It contains software that is required to make your computer work with your operating system. It does not lose its contents by disconnection of power.

18 Memory Measurement Bit All computers work on a binary numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is called a bit. Byte A byte consists of eight bits. Kilobyte A kilobyte (KB) consists of 1024 bytes. Megabyte A megabyte (MB) consists of 1024 kilobytes. Gigabyte A gigabyte (GB) consists of 1024 megabytes.

19 Main parts of the PC Storage Devices: 1. The internal Hard Disks: Internal hard disk are the main, large data storage area within your computer. used to store your operating system, your application programs (i.e. your word processor, games etc) and your data. They are much faster than CD-ROMs and floppy disks and can also hold much more data. The speed of a hard disk is often quoted as "average access time" speed, measured in milliseconds. The smaller this number the faster the disk. Often in excess of 10 Gigabytes.

20 Main parts of the PC 2. The external Hard Disks: Normally slower that internal disks, but more expensive versions offer the same performance as internal hard disks. Capacity: same as internal disks. Cost: More expensive than internal disks.

21 Main parts of the PC 3. Floppy Disk: They are very slow compared to hard disks or CD-ROMs, and hold relatively small amounts of data (1.44 Mbytes). Unreliable. 4. Zip Disk: Slower than normal hard disks but ideal for backups. Capacity: 100 or 250 Megabytes.

22 Main parts of the PC 5. Jaz Disk: Slower than normal hard disks but ideal for backups. Capacity: around 2 Gigabytes. 6. CD-ROM ( Compact Disc Read-only memory) & DVDs ( Digital Versatile Disc) : Similar to the audio devices familiar in home use but hold computer data rather than music. The storage capacity of CD reaches 750 megabyte, whereas the storage capacity of the DVD reaches more than 4 gigabytes.

23 Main parts of the PC Peripheral devices : A peripheral device is any device that you can attach to your computer.

24 Factors That Impact on a Computer's Performance CPU speed RAM size Hard disk speed and capacity

25 Components of a Computer System Central Processing Unit ( CPU ) control unit (CU) Arithmetic logic Unit (ALU) RAM ROM Memory Input units output units secondary Memory Data Information/ Knowledge

26 Lecture 2 - Conclusion The main parts of the Personal Computer Hardware Memory Measurement Factors That Impact on a Computer's Performance

27 Lecture 3- Next Week ! Computer Software


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